customizations.rst

Customizations

Spec validation

By default, the provided specification is validated on Spec object creation time.

If you know you have a valid specification already, disabling the validator can improve the performance.

from openapi_core import Spec

spec = Spec.from_dict(spec_dict, validator=None)

Deserializers

Pass custom defined media type deserializers dictionary with supported mimetypes as a key to MediaTypeDeserializersFactory and then pass it to RequestValidator or ResponseValidator constructor:

from openapi_core.deserializing.media_types.factories import MediaTypeDeserializersFactory

def protobuf_deserializer(message):
    feature = route_guide_pb2.Feature()
    feature.ParseFromString(message)
    return feature

custom_media_type_deserializers = {
    'application/protobuf': protobuf_deserializer,
}
media_type_deserializers_factory = MediaTypeDeserializersFactory(
    custom_deserializers=custom_media_type_deserializers,
)

result = validate_response(
    request, response,
    spec=spec,
    cls=V30ResponseValidator,
    media_type_deserializers_factory=media_type_deserializers_factory,
)

Formats

OpenAPI defines a format keyword that hints at how a value should be interpreted, e.g. a string with the type date should conform to the RFC 3339 date format.

Openapi-core comes with a set of built-in formatters, but it's also possible to add custom formatters in SchemaUnmarshallersFactory and pass it to RequestValidator or ResponseValidator.

Here's how you could add support for a usdate format that handles dates of the form MM/DD/YYYY:

from openapi_core.unmarshalling.schemas.factories import SchemaUnmarshallersFactory
from openapi_schema_validator import OAS30Validator
from datetime import datetime
import re

class USDateFormatter:
    def validate(self, value) -> bool:
        return bool(re.match(r"^\d{1,2}/\d{1,2}/\d{4}$", value))

    def format(self, value):
        return datetime.strptime(value, "%m/%d/%y").date


custom_formatters = {
    'usdate': USDateFormatter(),
}
schema_unmarshallers_factory = SchemaUnmarshallersFactory(
    OAS30Validator,
    custom_formatters=custom_formatters,
    context=UnmarshalContext.RESPONSE,
)

result = validate_response(
    request, response,
    spec=spec,
    cls=ResponseValidator,
    schema_unmarshallers_factory=schema_unmarshallers_factory,
)